The use of copolymers formed from tetrafluoroethylene (TFE) and perfluoro (propyl vinyl ether) (PPVE) for the insulation of wire is well known. The polymers have good heat resistance, and high resistance to solvent attack. These attributes are desirable for use in a wide variety of applications involving jacketing or covering of wire and cable constructions. Other desirable attributes in coverings for such applications include good mechanical properties such as resistance to abrasion and resistance to cut-through of insulation by sharp edges. However, the properties of these copolymers are poor in these respects.
Attempts have been made in the past to improve the mechanical properties of TFE copolymers by including additives such as glass spheres, silica flake and the like. However, the improvements achieved with such compositions are generally limited and often at the expense of other desirable features. For example, a degradation of electrical properties or mechanical properties, such as flexibility, can result.
Attempts have also been made in the past to improve the mechanical properties of the fluoropolymers by mixing with other polymers having better mechanical properties, such as polyphenylene sulphide, polyphenylene oxide, etc. However, these other polymers are in general incompatible with fluororpolymers so that there is difficulty in producing intimate blends.
The present invention attempts to mitigate some these problems.